A seat for an automobile, a train, various sofas, an office chair, or the like may be provided with a cushion body, and an epidermis material is disposed over the cushion body. This cushion body has been manufactured from so-called “rock wool,” which is made by interlacing a rigid fiber (e.g., a palm fiber, a hemp fiber, or a bold synthetic fiber) and firmly fixing it by a rubber or the like. Alternatively, this cushion body is molded from various types of foaming resin materials.
Typically, the cushion body has a curved face having a concavo-convex shape that is ergonomically satisfactory. For example, the shape of the cushion body allows a passenger to keep a relatively comfortable seating posture even if the passenger has been seated for a long time.
It is difficult to manufacture cushion bodies efficiently on a mass production basis using rock wool. However, a cushion body made of a foaming resin can be manufactured easily (e.g., by a single manufacturing step), and these cushion bodies can be made easily to have various shapes. For example, the cushion body made of a foaming resin can be obtained in such a manner that a foaming resin material (e.g., an urethane foam resin) is poured into a mold defining the desired shape, and the foaming resin material is molded into the desired shape simultaneously with foaming.
Once the cushion body has been molded, an epidermis material (e.g., various fiber cloths, natural or artificial leather) is integrally joined over the surface of the surface of the cushion body. To effect this integral mounting, the foaming resin material may be poured into the epidermis material to integrate the cushion body on the inner surface of the epidermis material at the same time as molding. Alternatively, the epidermis material may be slipped over and firmly fixed to the outer surface of the cushion body after the cushion body has been molded.
To mold the foaming resin material integrally within the epidermis material, the epidermis material is set along an inner face of the mold, and the epidermis material is absorbed along the inner face of the mold by using an absorbing means. However, to modify the epidermis material along with the surface of the cushion body that has the above-described curved surface, it is necessary for the epidermis material to be a material that is excellent in its elasticity. However, this process typically results in huge numbers of creases, particularly, between the seat face and the peripheral face, because the elasticity is limited depending on a material.
In addition, in this integral molding process, the cushion body and the epidermis material are integrated on the entire face of the cushion body. Thus, for example, when a strong force is applied in a certain direction that results in displacement of the epidermis material relative to the surface of the cushion body, a shear force is effected between the epidermis material and the cushion body. In many cases, this shear force may cause the cushion body to be partially sheared and the epidermis material to be separated. In addition, the materials capable of reducing the appearance of creases that can be used as epidermis materials are limited. Furthermore, a small amount of movement between the epidermis material and the cushion body should be expected, so materials capable of tolerating the small amount of movement are preferred. In light of these limitations and disadvantages of integrally molding the epidermis material at the same time as molding the cushion body, a method for applying the epidermis material to the cushion body that has been molded in advance has been employed in many cases.
According to a general method for applying the epidermis material to such a cushion body made of the foaming resin material, a male surface fastener member is integrally and firmly fixed on a particular region of the surface of the cushion body. The male surface fastener member has a narrow flat-type base material, and many hook-shaped engaging elements extend from one face of the base material. The male surface fastener member is integrally fixed on the surface of the cushion body such that the hook-shaped engaging elements are exposed (i.e., face away from the surface of the cushion body). The epidermis material includes a loop material as a female fastener member formed on certain portions of the inner surface of the epidermis material. Accordingly, when the epidermis material is slipped over the cushion body, the loop material on the inner surface of the epidermis material is pressed against the male surface fastener members on the cushion body to fix firmly the epidermis material to the cushion body.
The epidermis material may be made of various materials, such as a pile-woven knit fabric, a natural leather, or an artificial leather, and the materials may be formed in advance into a bag-like shape having the appearance of the cushion body. The epidermis material is slipped over the cushion body, and the female engaging elements arranged on the inner surface of the epidermis material are pressed against the engaging elements secured onto the outside surface of the cushion body. The epidermis material is joined and firmly fixed along the concave face of the cushion body, and uplift of the epidermis material from the cushion body is prevented.
To integrally and firmly fix the male surface fastener member to the cushion body, the engaging elements formed on the face of the male surface fastener member are disposed to face a projection face of a mold for molding a concave face of a cushion body according to the shape of the projection face. A foaming resin material is poured into the inside of the mold so as to foam and mold the cushion body, and at the same time, the male surface fastener member is partially buried in the face of the cushion body with the engaging elements of the male surface fastener member being exposed to the outside of the cushion body. When foaming and molding the cushion body, it is desirable to prevent the foaming resin material from being poured into the zone on which the engaging elements are formed.
To prevent the foaming resin material from intruding into the zone on which the engaging elements of the surface fastener are formed during molding of the cushion body, solid walls 104 and 105, as shown in FIGS. 20 and 21, have been integrally formed along a peripheral edge portion of a base material 102 of a surface fastener 110 so as to surround the engaging elements 103 along the longitudinal edges of the surface fastener 110. The lateral solid wall 104 shown in FIG. 20 is elongated in a width direction of the surface fastener and is disposed between adjacent segments, or groups, of surface fasteners. The lateral solid wall 104 prevents foaming resin from intruding between the fastener elements in a longitudinal direction. The height of the walls 104, 105 are slightly higher than the heights of the engaging elements surrounded by the walls 104, 105 to prevent the foaming resin from penetrating into the engaging elements zone. Examples of surface fasteners having these types of solid walls are disclosed in U.S. Pat. Nos. 5,061,540 and 5,766,723.
U.S. Pat. No. 5,061,540 describes a method of securely mounting and fixing the engaging element on the predetermined region of the convex face portion of the bottom face of the mold. In particular, in U.S. Pat. No. 5,061,540, a permanent magnet 108 (as shown in FIG. 21) is buried in the region of the mold adjacent to the portion on which the surface fastener is to be mounted, and a magnetic material 109 is formed in or attached to the base material of the surface fastener. Thus, when the surface fastener is positioned near the region of the mold having the magnet 108, the magnet 108 attracts the magnetic material 109 in the surface fastener toward the magnet 108.
The magnetic body 109 and the permanent magnet 108 may have a curved shape or a straight shape. For example, the permanent magnet 108 may be formed of a flexible material, such as a synthetic resin, having a ferrite magnet and a magnetic powder mixed therein, and the magnetic body 109 may be formed of a thin tape material and a wire made of steel. The magnetic body 109 may be integrally buried in the base material at the same time as molding of the surface fastener.
As described above, the longitudinal solid walls 105 of the surface fastener are described in U.S. Pat. Nos. 5,061,540 and 5,766,723, and these patents describe forming longitudinal walls 105 along the two longitudinal edges of the base material in a width direction on the face of the base material on which the engaging elements 103 are formed. The engaging elements are segmented into groups, defining zones of engaging elements, and the lateral walls 104 is positioned between these groups of engaging elements. Thus, the foaming resin material is prevented from intruding from the longitudinal and lateral directions due to the lateral and longitudinal solid walls 104, 105, respectively.
As noted above, in recent years, it has been popular to integrally mold the engaging elements and solid walls in succession and simultaneously on the surface of the base material by injecting or extruding a molten resin on a peripheral face of a die wheel that is rotatably driven in one direction. The peripheral face has many cavities for molding the engaging elements and the solid walls. However, if the molding surface fastener is to be long, the molding intervals of the lateral solid walls are determined by the number of rows of the engaging elements to be arranged between the lateral solid walls and an external diameter of the die wheel. Thus, repetition of a predetermined interval cannot be avoided.
On the other hand, to obtain a seating posture that is regarded as the most preferable posture from the viewpoint of ergonomics, a concave-convex face made by a moderate curved face is formed on a surface of a sheet for an automobile, for example. The shape of the concave-convex face, particularly the length thereof, is not fixed but varied. In addition, to obtain stability of the surface shape of the seat and stability of the seating posture, a plurality of linear recesses are formed so as to surround the peripheries of buttocks, a back portion, and a shoulder portion of the seat. In addition, the cushion body and the epidermis material are joined and integrated along the linear recesses. The male surface fastener member is integrated with the seat cushion body along the concave face portion of the seat of the seat cushion body having the concave-convex face and the liner recesses. Upon applying the epidermis material to the cushion body, pressure is applied to engage the female surface fastener zone on the inner surface of the epidermis material with the male engaging elements formed on the surface fastener.
Accordingly, the male surface fastener member needs to have a length corresponding to the length of the concave face portion of the cushion body, and the linear recess of various sized cushion bodies may have different lengths. Thus, it is necessary to cut the long male surface fastener into a required length depending on the length of the concave portion or linear recess of the cushion body. As a result, the long male surface fastener may be cut within the engaging element zone of the male surface fastener and not adjacent one of the lateral solid walls 104. When this occurs, the foaming resin material can intrude into the cut engaging element forming zone, which results in the engaging elements in this exposed area being buried in the foaming resin material, and the ability of the engaging elements in this zone to engage the female engaging material on the epidermis material is lost or compromised.
Particularly, in the conventional surface fasteners as disclosed in the above-described U.S. Pat. Nos. 5,061,540 and 5,766,723 and shown in FIG. 20, the spacing between the lateral solid walls 104 is limited by the spacing between the groups of engaging elements 103 formed on the surface of the base material 102 and the diameter of the die wheel, as noted above. Thus, the spacing of the lateral solid walls 104 is difficult to adjust to allow the fastener to be used in linear recesses having various different lengths. In addition, because engaging elements 103 cannot be formed on the base material 102 in the area of the lateral solid wall 104 and because engaging elements formed too close to the wall 104 would not be able to join effectively with corresponding female engaging elements, the effective engaging surface area of the surface fastener 110 is reduced by the thickness of the lateral solid walls 104 and an adequate amount of spacing between the lateral solid walls 104 and the rows of engaging elements 103 formed next to the walls 104. Thus, if the lateral solid walls 104 were positioned more closely together, the engaging force of the fastener member 110 would be reduced.
In addition, in many cases, a linear recess on the surface of the mold for forming the cushion body may be curved along a flat face of the mold in a direction that is substantially parallel with the surface of the cushion body. Prior art male surface fastener members are straight and are easily curved in a direction perpendicular to the surface of the base material so as to follow the linear recess. However, if the recess in the surface of the mold is curved in a width direction, the prior art male surface fastener member are not able to bend in the width direction of the base material to fit within the curved recess.
Therefore, for example, according to U.S. Pat. No. 6,656,563, short surface fastener strips are connected to each other via a hinge part that is flexible in a length direction, and the surface fastener strips are adjacent each other such that the surface fastener strips can be bent relatively in a horizontal direction for use in the curved linear recesses described above. Further, in the male surface fastener member described in U.S. Pat. No. 6,656,563, the foaming resin is prevented from intruding into the engaging element forming zone by a gasket formed around the perimeter of the face of the engaging element forming zone of the surface fastener strip or by providing a cover so as to cover the engaging element forming zone of the surface fastener strip.
The mold surface fastener member disclosed in U.S. Pat. No. 6,656,563 is manufactured by using a rotating die wheel on which various cavities are defined in a peripheral face thereof. The cavities define the shape of the engaging elements, the gasket, and the hinge. A molten resin is extruded or continuously injected toward the peripheral face of the rotating die wheel. These multiple cavities are arranged at predetermined intervals in the peripheral direction of the rotating die wheel and the axial direction thereof, which is a relatively complicated process and which results in increased manufacturing costs.
In addition, in some prior art surface fasteners, a cover is provided over the engaging elements of the surface fastener to prevent intrusion of the foaming resin into the areas between the engaging elements. This type of surface fastener requires an extra step of an operator having to remove the cover after the cushion body is formed to expose the engaging elements, which reduces the efficiency of the manufacturing process and increases installation costs, installation space, and waste.